Nanocomposite magnet and method of producing the same

Abstract

A nanocomposite magnet includes grains including a shell of a Re-TM-B phase and a core of a TM or TM-B phase. Re is a rare earth element, and TM is a transition metal.

What is claimed is: 
     
         1 . A nanocomposite magnet comprising:
 grains including a shell of a Re-TM-B phase and a core of a TM or TM-B phase,   wherein Re is a rare earth element, and TM is a transition metal.   
     
     
         2 . The nanocomposite magnet according to  claim 1 , wherein
 the grains are present in a Re-rich phase.   
     
     
         3 . The nanocomposite magnet according to  claim 1 , wherein
 TM is Fe, Co, Ni, or a combination of at least two of Fe, Co or Ni.   
     
     
         4 . The nanocomposite magnet according to  claim 1 , wherein
 Re is Nd, Y, La, Ce, Pr, Sm, Gd, Tb, Dy, or a combination of at least two of Nd, Y, La, Ce, Pr, Sm, Gd, Tb or Dy.   
     
     
         5 . The nanocomposite magnet according to  claim 1 , wherein
 Re is introduced to the nanocomposite magnet from a Re-M alloy, and   M is Ga, Zn, Si, Al, Fe, Co, Ni, Cu, Cr, Mg, Hg, Ag, or Au.   
     
     
         6 . The nanocomposite magnet according to  claim 1 , wherein
 Re is introduced to the nanocomposite magnet from a Re-M alloy, and   the Re-M alloy is a Nd—Cu alloy.   
     
     
         7 . A method of producing a nanocomposite magnet, the method comprising:
 bringing a phase including nano-sized TM-B grains having an average grain size of 1 μm or less into contact with a Re-M alloy;   heating the Re-M alloy to a melting point or higher to be melted; and   causing the molten Re-M alloy to diffusively penetrate into the TM-B grains,   wherein TM is a transition metal,   Re is a rare earth element, and   M is an element which decreases a melting point of the rare earth element when alloyed with the rare earth element.   
     
     
         8 . The method according to  claim 7 , wherein
 TM is Fe, Co, Ni, or a combination of at least two of Fe, Co or Ni.   
     
     
         9 . The method according to  claim 7 , wherein
 the TM-B grains are Fe—B grains.   
     
     
         10 . The method according to  claim 7 , wherein
 Re is Nd, Y, La, Ce, Pr, Sm, Gd, Tb, Dy, or a combination of at least two of Nd, Y, La, Ce, Pr, Sm, Gd, Tb or Dy.   
     
     
         11 . The method according to  claim 7 , wherein
 M is Ga, Zn, Si, Al, Fe, Co, Ni, Cu, Cr, Mg, Hg, Ag, or Au.   
     
     
         12 . The method according to  claim 7 , wherein
 the Re-M alloy is a Nd—Cu alloy.   
     
     
         13 . The method according to  claim 7 , wherein
 the average grain size of the TM-B grains is 10 nm to 1 μm.